Answer:
0.0376 or 3.76%.
Explanation:
The probability of drawing a red marble on the first draw is 5/21 because there are 5 red marbles out of 21 total marbles in the bag.
After the first draw, there are only 20 marbles left in the bag, so the probability of drawing a red marble on the second draw, without replacement, is 4/20 or 1/5.
Similarly, after the second draw, there are only 19 marbles left in the bag, so the probability of drawing a red marble on the third draw, without replacement, is 3/19.
To find the probability of all three marbles being red, we need to multiply the probabilities of each individual draw together:
(5/21) x (1/5) x (3/19) = 15/399 or approximately 0.0376.
Therefore, the probability of drawing three red marbles in a row, without replacement, is about 0.0376 or 3.76%.